Calm down, just as they like to make a good show of making the convicted go on tv and denounce their American capitalist overlords, the 15 yrs hard labour is also likely about show.
History indicates the Westerners that are ‘made example of’ and get harsh sentences are often quietly released a couple of years later. Which is no walk in park I’m sure, but it’s not 15 yrs at least!
Ultimately any guy looking for Christian converts in North Korea must know he’s dancing with the Devil, right from the start, I should think.